The present invention relates generally to a device for measuring the rotation of a rotating element and, more particularly to a device that contains a magnetic encoder to be maintained in the vicinity of a sensor.
Conventionally, devices for measuring the angular position or the speed of a rotating element contain a sensor, which is maintained immobile with respect to the measurement reference frame, and a magnetic encoder driven in rotation by the shaft, the sensor cooperating with the magnetic encoder in order to provide a signal to an electronic station that processes the information. Such devices have the disadvantage of requiring an air gap between the magnetic encoder and the sensor. A variation of the air gap, for example in the case of extensive vibrations of the rotating element, can lead to incorrect information.
In order to remedy this difficulty, a known method is to use a means of application, such as an elastic washer, in order to maintain the magnetic encoder in close proximity to the sensor. An example of this type of device is described and represented in the document FR-A-2 688 606 submitted by the applicant. However, this solution leads to a rather complex device, which contains numerous pieces to be assembled, thus generating a large space requirement and a high cost of the device, which makes it poorly suited to the simplest applications.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. An object of the present invention is therefore to propose a device for measuring the rotation of a rotating element which has a small space requirement and which ensures good positioning and maintaining of a constant air gap between the magnetic encoder and the sensor and which is simple and economical to realize. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.